Merge branch 'akpm' (patches from Andrew)

Merge yet more updates from Andrew Morton:

 - lots of little subsystems

 - a few post-linux-next MM material. Most of the rest awaits more
   merging of other trees.

Subsystems affected by this series: alpha, procfs, misc, core-kernel,
bitmap, lib, lz4, checkpatch, nilfs, kdump, rapidio, gcov, bfs, relay,
resource, ubsan, reboot, fault-injection, lzo, apparmor, and mm (swap,
memory-hotplug, pagemap, cleanups, and gup).

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (86 commits)
  mm: fix some spelling mistakes in comments
  mm: simplify follow_pte{,pmd}
  mm: unexport follow_pte_pmd
  apparmor: remove duplicate macro list_entry_is_head()
  lib/lzo/lzo1x_compress.c: make lzogeneric1x_1_compress() static
  fault-injection: handle EI_ETYPE_TRUE
  reboot: hide from sysfs not applicable settings
  reboot: allow to override reboot type if quirks are found
  reboot: remove cf9_safe from allowed types and rename cf9_force
  reboot: allow to specify reboot mode via sysfs
  reboot: refactor and comment the cpu selection code
  lib/ubsan.c: mark type_check_kinds with static keyword
  kcov: don't instrument with UBSAN
  ubsan: expand tests and reporting
  ubsan: remove UBSAN_MISC in favor of individual options
  ubsan: enable for all*config builds
  ubsan: disable UBSAN_TRAP for all*config
  ubsan: disable object-size sanitizer under GCC
  ubsan: move cc-option tests into Kconfig
  ubsan: remove redundant -Wno-maybe-uninitialized
  ...

87 files changed, 1568 insertions, 724 deletions

diff --git a/Documentation/ABI/testing/sysfs-kernel-reboot b/Documentation/ABI/testing/sysfs-kernel-reboot
new file mode 100644
index 000000000000..837330fb2511
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-kernel-reboot
@@ -0,0 +1,32 @@
+What:		/sys/kernel/reboot
+Date:		November 2020
+KernelVersion:	5.11
+Contact:	Matteo Croce <mcroce@microsoft.com>
+Description:	Interface to set the kernel reboot behavior, similarly to
+		what can be done via the reboot= cmdline option.
+		(see Documentation/admin-guide/kernel-parameters.txt)
+
+What:		/sys/kernel/reboot/mode
+Date:		November 2020
+KernelVersion:	5.11
+Contact:	Matteo Croce <mcroce@microsoft.com>
+Description:	Reboot mode. Valid values are: cold warm hard soft gpio
+
+What:		/sys/kernel/reboot/type
+Date:		November 2020
+KernelVersion:	5.11
+Contact:	Matteo Croce <mcroce@microsoft.com>
+Description:	Reboot type. Valid values are: bios acpi kbd triple efi pci
+
+What:		/sys/kernel/reboot/cpu
+Date:		November 2020
+KernelVersion:	5.11
+Contact:	Matteo Croce <mcroce@microsoft.com>
+Description:	CPU number to use to reboot.
+
+What:		/sys/kernel/reboot/force
+Date:		November 2020
+KernelVersion:	5.11
+Contact:	Matteo Croce <mcroce@microsoft.com>
+Description:	Don't wait for any other CPUs on reboot and
+		avoid anything that could hang.
diff --git a/Documentation/admin-guide/kdump/vmcoreinfo.rst b/Documentation/admin-guide/kdump/vmcoreinfo.rst
index e44a6c01f336..3861a25faae1 100644
--- a/Documentation/admin-guide/kdump/vmcoreinfo.rst
+++ b/Documentation/admin-guide/kdump/vmcoreinfo.rst
@@ -39,6 +39,12 @@ call.
 User-space tools can get the kernel name, host name, kernel release
 number, kernel version, architecture name and OS type from it.
 
+(uts_namespace, name)
+---------------------
+
+Offset of the name's member. Crash Utility and Makedumpfile get
+the start address of the init_uts_ns.name from this.
+
 node_online_map
 ---------------
 
diff --git a/Documentation/dev-tools/ubsan.rst b/Documentation/dev-tools/ubsan.rst
index 655e6b63c227..1be6618e232d 100644
--- a/Documentation/dev-tools/ubsan.rst
+++ b/Documentation/dev-tools/ubsan.rst
@@ -86,3 +86,4 @@ References
 
 .. _1: https://gcc.gnu.org/onlinedocs/gcc-4.9.0/gcc/Debugging-Options.html
 .. _2: https://gcc.gnu.org/onlinedocs/gcc/Debugging-Options.html
+.. _3: https://clang.llvm.org/docs/UndefinedBehaviorSanitizer.html
diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst
index e5fa972d4c76..2fa69f710e2a 100644
--- a/Documentation/filesystems/proc.rst
+++ b/Documentation/filesystems/proc.rst
@@ -210,6 +210,7 @@ read the file /proc/PID/status::
   NoNewPrivs:     0
   Seccomp:        0
   Speculation_Store_Bypass:       thread vulnerable
+  SpeculationIndirectBranch:      conditional enabled
   voluntary_ctxt_switches:        0
   nonvoluntary_ctxt_switches:     1
 
@@ -292,6 +293,7 @@ It's slow but very precise.
  NoNewPrivs                  no_new_privs, like prctl(PR_GET_NO_NEW_PRIV, ...)
  Seccomp                     seccomp mode, like prctl(PR_GET_SECCOMP, ...)
  Speculation_Store_Bypass    speculative store bypass mitigation status
+ SpeculationIndirectBranch   indirect branch speculation mode
  Cpus_allowed                mask of CPUs on which this process may run
  Cpus_allowed_list           Same as previous, but in "list format"
  Mems_allowed                mask of memory nodes allowed to this process
diff --git a/arch/alpha/kernel/process.c b/arch/alpha/kernel/process.c
index 4c7b0414a3ff..6c71554206cc 100644
--- a/arch/alpha/kernel/process.c
+++ b/arch/alpha/kernel/process.c
@@ -134,7 +134,7 @@ common_shutdown_1(void *generic_ptr)
 #ifdef CONFIG_DUMMY_CONSOLE
 		/* If we've gotten here after SysRq-b, leave interrupt
 		   context before taking over the console. */
-		if (in_interrupt())
+		if (in_irq())
 			irq_exit();
 		/* This has the effect of resetting the VGA video origin.  */
 		console_lock();
diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S
index 6db90cdf11da..e184d17387f6 100644
--- a/arch/powerpc/kernel/vmlinux.lds.S
+++ b/arch/powerpc/kernel/vmlinux.lds.S
@@ -313,6 +313,10 @@ SECTIONS
 #else
 	.data : AT(ADDR(.data) - LOAD_OFFSET) {
 		DATA_DATA
+#ifdef CONFIG_UBSAN
+		*(.data..Lubsan_data*)
+		*(.data..Lubsan_type*)
+#endif
 		*(.data.rel*)
 		*(.toc1)
 		*(.branch_lt)
diff --git a/arch/s390/pci/pci_mmio.c b/arch/s390/pci/pci_mmio.c
index de3bdbed8881..18f2d10c3176 100644
--- a/arch/s390/pci/pci_mmio.c
+++ b/arch/s390/pci/pci_mmio.c
@@ -170,7 +170,7 @@ SYSCALL_DEFINE3(s390_pci_mmio_write, unsigned long, mmio_addr,
 	if (!(vma->vm_flags & VM_WRITE))
 		goto out_unlock_mmap;
 
-	ret = follow_pte_pmd(vma->vm_mm, mmio_addr, NULL, &ptep, NULL, &ptl);
+	ret = follow_pte(vma->vm_mm, mmio_addr, NULL, &ptep, NULL, &ptl);
 	if (ret)
 		goto out_unlock_mmap;
 
@@ -311,7 +311,7 @@ SYSCALL_DEFINE3(s390_pci_mmio_read, unsigned long, mmio_addr,
 	if (!(vma->vm_flags & VM_WRITE))
 		goto out_unlock_mmap;
 
-	ret = follow_pte_pmd(vma->vm_mm, mmio_addr, NULL, &ptep, NULL, &ptl);
+	ret = follow_pte(vma->vm_mm, mmio_addr, NULL, &ptep, NULL, &ptl);
 	if (ret)
 		goto out_unlock_mmap;
 
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_log.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_log.c
index 9bbe8a795cb8..c92f2c056db4 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_log.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_log.c
@@ -134,7 +134,7 @@ static int remove_buf_file_callback(struct dentry *dentry)
 }
 
 /* relay channel callbacks */
-static struct rchan_callbacks relay_callbacks = {
+static const struct rchan_callbacks relay_callbacks = {
 	.subbuf_start = subbuf_start_callback,
 	.create_buf_file = create_buf_file_callback,
 	.remove_buf_file = remove_buf_file_callback,
diff --git a/drivers/misc/lkdtm/Makefile b/drivers/misc/lkdtm/Makefile
index 1ef7888a12b5..7727bfd32be9 100644
--- a/drivers/misc/lkdtm/Makefile
+++ b/drivers/misc/lkdtm/Makefile
@@ -10,6 +10,7 @@ lkdtm-$(CONFIG_LKDTM)		+= rodata_objcopy.o
 lkdtm-$(CONFIG_LKDTM)		+= usercopy.o
 lkdtm-$(CONFIG_LKDTM)		+= stackleak.o
 lkdtm-$(CONFIG_LKDTM)		+= cfi.o
+lkdtm-$(CONFIG_LKDTM)		+= fortify.o
 
 KASAN_SANITIZE_rodata.o		:= n
 KASAN_SANITIZE_stackleak.o	:= n
diff --git a/drivers/misc/lkdtm/bugs.c b/drivers/misc/lkdtm/bugs.c
index a0675d4154d2..110f5a8538e9 100644
--- a/drivers/misc/lkdtm/bugs.c
+++ b/drivers/misc/lkdtm/bugs.c
@@ -482,3 +482,53 @@ noinline void lkdtm_CORRUPT_PAC(void)
 	pr_err("XFAIL: this test is arm64-only\n");
 #endif
 }
+
+void lkdtm_FORTIFY_OBJECT(void)
+{
+	struct target {
+		char a[10];
+	} target[2] = {};
+	int result;
+
+	/*
+	 * Using volatile prevents the compiler from determining the value of
+	 * 'size' at compile time. Without that, we would get a compile error
+	 * rather than a runtime error.
+	 */
+	volatile int size = 11;
+
+	pr_info("trying to read past the end of a struct\n");
+
+	result = memcmp(&target[0], &target[1], size);
+
+	/* Print result to prevent the code from being eliminated */
+	pr_err("FAIL: fortify did not catch an object overread!\n"
+	       "\"%d\" was the memcmp result.\n", result);
+}
+
+void lkdtm_FORTIFY_SUBOBJECT(void)
+{
+	struct target {
+		char a[10];
+		char b[10];
+	} target;
+	char *src;
+
+	src = kmalloc(20, GFP_KERNEL);
+	strscpy(src, "over ten bytes", 20);
+
+	pr_info("trying to strcpy past the end of a member of a struct\n");
+
+	/*
+	 * strncpy(target.a, src, 20); will hit a compile error because the
+	 * compiler knows at build time that target.a < 20 bytes. Use strcpy()
+	 * to force a runtime error.
+	 */
+	strcpy(target.a, src);
+
+	/* Use target.a to prevent the code from being eliminated */
+	pr_err("FAIL: fortify did not catch an sub-object overrun!\n"
+	       "\"%s\" was copied.\n", target.a);
+
+	kfree(src);
+}
diff --git a/drivers/misc/lkdtm/core.c b/drivers/misc/lkdtm/core.c
index 97803f213d9d..3c0a67f072c0 100644
--- a/drivers/misc/lkdtm/core.c
+++ b/drivers/misc/lkdtm/core.c
@@ -117,6 +117,8 @@ static const struct crashtype crashtypes[] = {
 	CRASHTYPE(UNSET_SMEP),
 	CRASHTYPE(CORRUPT_PAC),
 	CRASHTYPE(UNALIGNED_LOAD_STORE_WRITE),
+	CRASHTYPE(FORTIFY_OBJECT),
+	CRASHTYPE(FORTIFY_SUBOBJECT),
 	CRASHTYPE(OVERWRITE_ALLOCATION),
 	CRASHTYPE(WRITE_AFTER_FREE),
 	CRASHTYPE(READ_AFTER_FREE),
@@ -173,6 +175,7 @@ static const struct crashtype crashtypes[] = {
 	CRASHTYPE(USERCOPY_KERNEL),
 	CRASHTYPE(STACKLEAK_ERASING),
 	CRASHTYPE(CFI_FORWARD_PROTO),
+	CRASHTYPE(FORTIFIED_STRSCPY),
 #ifdef CONFIG_X86_32
 	CRASHTYPE(DOUBLE_FAULT),
 #endif
diff --git a/drivers/misc/lkdtm/fortify.c b/drivers/misc/lkdtm/fortify.c
new file mode 100644
index 000000000000..faf29cf04baa
--- /dev/null
+++ b/drivers/misc/lkdtm/fortify.c
@@ -0,0 +1,82 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2020 Francis Laniel <laniel_francis@privacyrequired.com>
+ *
+ * Add tests related to fortified functions in this file.
+ */
+#include "lkdtm.h"
+#include <linux/string.h>
+#include <linux/slab.h>
+
+
+/*
+ * Calls fortified strscpy to test that it returns the same result as vanilla
+ * strscpy and generate a panic because there is a write overflow (i.e. src
+ * length is greater than dst length).
+ */
+void lkdtm_FORTIFIED_STRSCPY(void)
+{
+	char *src;
+	char dst[5];
+
+	struct {
+		union {
+			char big[10];
+			char src[5];
+		};
+	} weird = { .big = "hello!" };
+	char weird_dst[sizeof(weird.src) + 1];
+
+	src = kstrdup("foobar", GFP_KERNEL);
+
+	if (src == NULL)
+		return;
+
+	/* Vanilla strscpy returns -E2BIG if size is 0. */
+	if (strscpy(dst, src, 0) != -E2BIG)
+		pr_warn("FAIL: strscpy() of 0 length did not return -E2BIG\n");
+
+	/* Vanilla strscpy returns -E2BIG if src is truncated. */
+	if (strscpy(dst, src, sizeof(dst)) != -E2BIG)
+		pr_warn("FAIL: strscpy() did not return -E2BIG while src is truncated\n");
+
+	/* After above call, dst must contain "foob" because src was truncated. */
+	if (strncmp(dst, "foob", sizeof(dst)) != 0)
+		pr_warn("FAIL: after strscpy() dst does not contain \"foob\" but \"%s\"\n",
+			dst);
+
+	/* Shrink src so the strscpy() below succeeds. */
+	src[3] = '\0';
+
+	/*
+	 * Vanilla strscpy returns number of character copied if everything goes
+	 * well.
+	 */
+	if (strscpy(dst, src, sizeof(dst)) != 3)
+		pr_warn("FAIL: strscpy() did not return 3 while src was copied entirely truncated\n");
+
+	/* After above call, dst must contain "foo" because src was copied. */
+	if (strncmp(dst, "foo", sizeof(dst)) != 0)
+		pr_warn("FAIL: after strscpy() dst does not contain \"foo\" but \"%s\"\n",
+			dst);
+
+	/* Test when src is embedded inside a union. */
+	strscpy(weird_dst, weird.src, sizeof(weird_dst));
+
+	if (strcmp(weird_dst, "hello") != 0)
+		pr_warn("FAIL: after strscpy() weird_dst does not contain \"hello\" but \"%s\"\n",
+			weird_dst);
+
+	/* Restore src to its initial value. */
+	src[3] = 'b';
+
+	/*
+	 * Use strlen here so size cannot be known at compile time and there is
+	 * a runtime write overflow.
+	 */
+	strscpy(dst, src, strlen(src));
+
+	pr_warn("FAIL: No overflow in above strscpy()\n");
+
+	kfree(src);
+}
diff --git a/drivers/misc/lkdtm/lkdtm.h b/drivers/misc/lkdtm/lkdtm.h
index 6dec4c9b442f..6aa6d6a1a839 100644
--- a/drivers/misc/lkdtm/lkdtm.h
+++ b/drivers/misc/lkdtm/lkdtm.h
@@ -6,7 +6,7 @@
 
 #include <linux/kernel.h>
 
-/* lkdtm_bugs.c */
+/* bugs.c */
 void __init lkdtm_bugs_init(int *recur_param);
 void lkdtm_PANIC(void);
 void lkdtm_BUG(void);
@@ -32,8 +32,10 @@ void lkdtm_STACK_GUARD_PAGE_TRAILING(void);
 void lkdtm_UNSET_SMEP(void);
 void lkdtm_DOUBLE_FAULT(void);
 void lkdtm_CORRUPT_PAC(void);
+void lkdtm_FORTIFY_OBJECT(void);
+void lkdtm_FORTIFY_SUBOBJECT(void);
 
-/* lkdtm_heap.c */
+/* heap.c */
 void __init lkdtm_heap_init(void);
 void __exit lkdtm_heap_exit(void);
 void lkdtm_OVERWRITE_ALLOCATION(void);
@@ -45,7 +47,7 @@ void lkdtm_SLAB_FREE_DOUBLE(void);
 void lkdtm_SLAB_FREE_CROSS(void);
 void lkdtm_SLAB_FREE_PAGE(void);
 
-/* lkdtm_perms.c */
+/* perms.c */
 void __init lkdtm_perms_init(void);
 void lkdtm_WRITE_RO(void);
 void lkdtm_WRITE_RO_AFTER_INIT(void);
@@ -60,7 +62,7 @@ void lkdtm_EXEC_NULL(void);
 void lkdtm_ACCESS_USERSPACE(void);
 void lkdtm_ACCESS_NULL(void);
 
-/* lkdtm_refcount.c */
+/* refcount.c */
 void lkdtm_REFCOUNT_INC_OVERFLOW(void);
 void lkdtm_REFCOUNT_ADD_OVERFLOW(void);
 void lkdtm_REFCOUNT_INC_NOT_ZERO_OVERFLOW(void);
@@ -81,10 +83,10 @@ void lkdtm_REFCOUNT_SUB_AND_TEST_SATURATED(void);
 void lkdtm_REFCOUNT_TIMING(void);
 void lkdtm_ATOMIC_TIMING(void);
 
-/* lkdtm_rodata.c */
+/* rodata.c */
 void lkdtm_rodata_do_nothing(void);
 
-/* lkdtm_usercopy.c */
+/* usercopy.c */
 void __init lkdtm_usercopy_init(void);
 void __exit lkdtm_usercopy_exit(void);
 void lkdtm_USERCOPY_HEAP_SIZE_TO(void);
@@ -96,10 +98,13 @@ void lkdtm_USERCOPY_STACK_FRAME_FROM(void);
 void lkdtm_USERCOPY_STACK_BEYOND(void);
 void lkdtm_USERCOPY_KERNEL(void);
 
-/* lkdtm_stackleak.c */
+/* stackleak.c */
 void lkdtm_STACKLEAK_ERASING(void);
 
 /* cfi.c */
 void lkdtm_CFI_FORWARD_PROTO(void);